This invention relates to a steering wheel core constructed so that at least the core pieces of the spoke parts extending between the boss and the core piece of the ring part are formed by die casting an aluminum alloy.
It has been proposed to form the steering wheel core by die casting an aluminum alloy for the purpose of decreasing the weight of the steering wheel and facilitating the production thereof.
Where the core pieces of the spoke parts interconnecting the boss and the ring part of the steering wheel are to be formed by die casting an aluminum alloy, the aluminum alloy to be used is desired to be of the type rich in extensibility in view of the performance the steering wheel core is required to exhibit. In all the six grades of die casting aluminum alloy (ADC1, ADC3, ADC5, ADC6, ADC10, and ADC12) designated by Japanese Industrial Standard (JIS), the grade ADC6 of rich ductility seems a feasible selection.
The adoption of ADC6, however, has not brought about fully satisfactory results.